Drive mechanism for ganged condensers and the like



July 22 1947. R! R A T I I 2,424,291

DRIVE MECHANISM FOR GANGED CONDENSERS AND THE LIKE Filed Aug. 7, 1945 2 Sheets-Sheet -1 fillllllll Iiilll- 1mm numnr L All INVENTOR Bf/CHARD R. STODDART ATTORNEY July 22, 1947. STODDART 2,424,291

DRIVE MECHANISM FOR GANGED CONDENSERS AND THE LIKE Filed Aug. 7, 1945 2 Sheets-Sheet 2 K 4 IV/ /4 /2.

INVEN TOR. RICHARD R. s TODDA RT ATTORNEY Patented July 22, 1947 DRIVE MECHANISM FOR GANGED CONDENSERS AND THE LIKE Richard R. Stoddart, Los Angeles, Calif. Application Augusti, 1945, Serial No. 609,378

4 Claims.

This invention relates to Vernier drive mechanisms, and pertains particularly to such mechanisms in combination with a multiple drive such as may be employed in radio devices for securing concurrent movement of a plurality of adjustable elements, as exemplified b ganged condensers, inductances, or the like.

A particular object of the invention is to provide a Vernier construction adapted for use as a trimming drive, where minor movement of one of a plurality of rotatably mounted members is desired, independent of the rotation of the other members of such plurality.

A further object of the invention is to provide a Vernier drive mechanism adapted for trimming the rotative adjustment or setting of one of a plurality of rotatably mounted devices normally adapted for concurrent rotation, wherein the Vernier drive mechanism is carried by the mechanism for producing the concurrent rotation so as to be in operative position at all rotative positions of such devices.

The device of the present invention may com prise, essentially, a main drive member adapted to be rotated to accomplish a principal rotation of a given rotatively mounted device such as a condenser, inductance, rheostat or the like, carrying an eccentric member rotatively mounted thereupon at a position removedfrom the center of rotation of said main drive member, a yoke member subtending said eccentric member and constrained to rotative movement about said center of rotation upon rotation of said main drive member, said yoke member being operatively associated with the given rotatively mounted device, together with means for rotating said eccentric member to cause relative movement of said yoke member with respect to said main drive member. The means for rotating said eccentric preferably comprises gear means including a pinion gear and an associated operating knob member or the like mounted for rotation about said center of rotation.

Other objects or features of the invention will be brought out in the ensuing description of an illustrative embodiment thereof, or will be apparent therefrom, The accompanying drawings illustrate the embodiment, and referring thereto:

Fig. 1 is a partly broken away front view of a construction embodying three drive assemblies constituting a main drive mechanism, two of which assemblies are provided with Vernier drive means according to this invention for causing minor rotation of either of these two assemblies independent of the rotation of the other assemblies;

Fig. 2 is a horizontal sectional view thereof, as taken on line 22 in Fig. 1; and

Fig. 3 is a partly broken away fragmentary perspective, in partly exploded condition, illustrating the Vernier drive means on a greater scale than is shown in Figs. 1 and 2.

Referring to the drawings, an embodiment of this invention is shown applied to a ganged condenser assembly, where concurrent rotation of all condensers is desired as a general object, and a minor movement of each but one of the condensers, independently of one another, is desired for the purpose of trimming the several condensers into a condition of balance, for example, Three separate variable condensers are shown at A, B, and C, each of the condensers comprising a stator structure 2, a rotor structure 3, and drive shafts 4 for the rotor structures. The whole assembly is preferably mounted upon a frame or chassis I. The condenser A may be considered as the reference condenser, with respect to which the condensers B and C are to be trimmed in use. For this purpose the condenser A is direct-driven through a drive member such as a gear 5 which may be direct-connected to an operating knob, or, as specifically shown, meshed with a gear sector I mounted upon an adjacent gear 8 associated with the condenser B and driven through pinion 9 associated with a reduction gearing I0 and driven therethrough by an operating knob 6.

The gear 8 is meshed with a similar gear II associated with the condenser C. The shafts of the condensers B and C are each rotatively secured to a yoke member I2. The yoke members I2 are provided with fingers I2a subtending an eccentric I3 mounted for rotation upon a stud I4 carried by each of the respective gears 8 and II at a position removed from the axis of rotation thereof. Attached to each of the eccentrics I3 is a Vernier gear I5 which is meshed with a drive pinion I6 connected to a vernier or trim knob I I, the pinion I6 being conveniently supported by a reduced diameter pilot shaft portion I8 formed as an extension of the shaft 4 so as to be disposed co-axially with respect to the shaft 4. The gears 8 and II are free of the respective shafts 4, and rotation of the gear 8 through the knob 6 and gear portion 1 will cause direct r0- tation of gear 5 and its associated condenser A. The rotation of the shafts associated with condensers B and C is indirect, through the linkage provided by the eccentrics I3 and yokes I2. Rotation of the gear II, for example, carries the stud I4 and the eccentric I3 about the center of rotation of the gear II, rotating the associated yoke I2 which is secured to the shaft 4. The trimming or Vernier movement of either of the condensers B or C is effected by rotating the associated trim knob ll, rotating the pinion I6 and the Vernier gear I5, which in turn rotates the associated eccentric I3 moves the yoke I2 rotatively about the axis of the shaft 4 and thus rotates the associated condenser shaft. An example of such 3 movement is illustrated in Fig. 3 by the full-line and dot-dash line positions of eccentric l3 and yoke 12.

As shown in Fig. 1, the assembly may be provided with an indicator or scale member 20, I- tatively associated with one of the gears 5, 8 or i I. For purposes of symmetry, the scale member 2 is shown as associated with the gear 8, through idler gears 2|, 22 and 23. It will be appreciated that the position of the gears 5, 8 and ii is dependent solely upon the rotative position of the shaft 4 associated with the condenser A, whichhas been taken as the reference condenser for the assembly. Adjustment of the trim knobs I! thus makes no change in the rotative position of the scale member 2, Wherefore calibration of the instrument made with respect to the reference condenser A will remain constant at all adjusted positions of the trim knobs.

As the gears 8 and H are rotated through themain drive means 6, 9 and HI, the Vernier gears 15 will be moved about the axis of the gears without rotation unless the associated trim knob l? is held against rotation. If the trim knob IT is held While the gear I l is rotated, for example, a minor rotation of the associated gear l and eccentric [3 will result, changing the setting of the yoke 12 slightly.

While I have shown the main drive members for the ganged drive assembly as comprised of gears 5, 8 and il, it will be appreciated that a fully equivalent structure may be attained through belt-connected pulleys or the like, without departing from the spirit and scope of my invention. For this and other equally obvious reasons I do not consider my invention to be limited to the specific details of construction herein delineated and described, but rather to the scope of the subjoined claims.

I claim:

1. A vernier drive mechanism for use in connection with a ganged drive adapted for concurrent rotation of a plurality of rotatable members, which comprises: a rotatable drive member associated with and adapted to be rotated upon operation of such ganged drive; a, shaft member coaxial with said drive member and adapted for rotative movement independent of said drive member, said shaft member being connected to one of said plurality of rotatable members; an eccentric member rotatively mounted on said drive member at a position removed from the axis of rotation thereof; a yoke member secured to said shaft member and subtending said eccentric member; and means for rotating said eccentric member to effect minor rotative movement of said shaft member with respect to said drive member.

2. A Vernier drive mechanism for use in connection with a ganged drive adapted for concurrent rotation of aplurality ofrotatable members, which comprises: a rotatable drive gear asrespective eccentric members sociated with and adapted to be rotated upon operation of such ganged drive; a shaft member coaxial with said drive gear and adapted for rotation independent of said drive gear, said shaft member being connected to one of said plurality of rotatable members; an eccentric member rotatively mounted on said drive gear at a position removed from the axis of rotation thereof; a yoke member secured to said shaft member and subtending said eccentric member; a gear member secured to said eccentric member for effecting rotation thereof; and drive means for said gear memberincluding a pinion gear meshing with said gear member and mounted for rotation co-axially with said shaft member.

3; In a drive assembly for concurrent rotation of a plurality of rotatable members, one of which constitutes a reference rotatable member, together with a Vernier drive mechanism for independent minor rotation of other rotatable members of said plurality with respect to said one reference member, the construction which comprises: a rotatable 'drive member for each of said rotatabl'emembers, the drive member for said one reference'member being direct connected to said one member, and said drive members being interconnected for concurrent rotation; each of said other rotatable members being provided with a shaft member adapted for rotation therewith and extending coaxially with respect to, but rotatively independent of, the associated drive member; an eccentric member rotatably mounted on each of the drive members associated with said other rotatable members, said eccentric members being respectively mounted at positions removed from the axes of rotation of such drive members; a yoke secured to each of the respective shaft members and subtending the respective eccentric member; and means for rotating the respective eccentric members independently of one another.

4. A construction as set forth in claim 3, said rotatabledrive members comprising a plurality of meshed gears, and said means for rotating the including gear members secured to the respective eccentric members for effecting rotation thereof, and pinion gear means mounted for rotation coaxially with the respective shaft members and meshing with the respective gear members.

RICHARD R. STODDART.

REFERENCES CITED The following references are of recordin the 

